(US4874999-A)      The automatic control system includes two control circuits, at least the second control circuit includes a proportional circuit and a differentiation circuit in addition to an integration circuit. When an object is controlled by switching from the first control circuit to the second circuit, an error signal between a target signal and a feedback signal is first applied to the integration circuit of the second control circuit, and after the lapse of predetermined time, the error signal is applied to the proportional circuit and the differentiation circuit of the second control circuit.    Jumping phenomenon is prevented which would be caused from the proportional circuit and the differentiation circuit.    USE -   For computer controlled governor in hydraulic power plant.    (EP318006-B1)      An automatic control system for controlling an object comprising: a first control circuit (x1, y1) and a second control circuit (x2, y2) each including an integration circuit (2; 12) receiving an error signal between a target signal (x1, x2) and a feedback signal, at least one of a proportional circuit (3; 13) and a differentiation circuit (6; 16) receiving the error signal, and an adder circuit (7, 17) for adding an output of the integration circuit (2; 12) to an output of at least one of the proportional circuit (3; 13) and te differentiation circuit (6; 16) the feedback signal being provided by an output of the adder circuit (7; 17); a selection circuit (SW, 10, SW 20) for selecting one of the outputs (y1. y2) of the first and second control circuits; first means (SW21) for applying the error signal of the second control circuit to the input of the integration circuit (12) of the second control circuit when control of the object is switched from the output (y1) of the first control circuit to the output (y2) of the second control circuit; and second means (SWD 21, SWD 22) for applying the error signal fo the second control circuit to at least one of the proportional circuit (13) and the differentiation circuit (16) of the second control circuit, after the lapse of a predetermined time following the operation of the first means.